The present invention is a method and apparatus for retaining or holding external articles to packframes. The invention is particularly well adapted for retaining articles such as tents, sleeping bags, or other bulky or akwardly shaped articles which do not readily fit into a normal packsack.
Man has been carrying loads on his back since time immemorial. Quite probably he has been looking for ways to make this task easier and less unpleasant for the same period of time. In recent years, this method of transport has evolved from a necessity of life into the recreational activity known as backpacking. Backpacking today has become so popular that authorities are limiting access to certain areas in order to prevent ecological damage from heavy hiker traffic.
No small part of the current popularity of backpacking can be attributed to the availability of well designed, lightweight equipment. This includes items such as tents, stoves, sleeping bags, and other articles which are necessities for being comfortable and safe while hiking or camping in areas remote from vehicular transportation. A key item has been the development, largely subsequent to World War II, of ergonomically engineered lightweight packframes which support the load carrying packbag.
Ideally, the load center of a pack should be located as nearly as possible to the wearer's center of gravity, or on a line passing through the wearer's center of gravity. Packbags, or "knapsacks", were originally no more than a flexible bag having a pair of shoulder straps or a tumpline which was supported by the wearers forehead. These caused the wearer to bend forward while traveling in order to place the load more nearly in a line above the hips and legs. As the knapsack evolved it was attached to an external wooden framework, or occasionally had an internal metallic framework, so that the load center would lie closer to the back. Ultimately, the packframe was lengthened and a broad strap which rested on the top of the buttocks was added at the lower end. This development was effective in transferring a significant percentage of the load from the relatively weak back and shoulders to the much stronger pelvic and leg structure. At the same time a waist strap was often added to maintain the lower portion of the packframe in close contact with the body. A well designed and properly loaded packframe of this type can be carried with relatively little downward force on the shoulders and without the need for bending forward to balance the load.
There are abundant examples of packframes of the above type in the patent literature. The following U.S. Patents can be regarded as exemplary U.S. Pat. Nos.: Renard, 1,040,413; Romney, 3,648,907; Joseph, 3,889,859; Fenner, 4,087,031; and Chanter, 4,361,259. Dean, II et al., in U.S. Pat. No. 3,923,217 show a dual purpose tubular metal packframe which can be dismantled at a camp to serve as a tent framework.
Very often the demands of a particular trip will require the wearer to carry relatively large loads. In extreme circumstances these may be as high as 35 to 50 kg. Seldom can a load of this magnitude be retained within the packbag normally supplied with a packframe. Most hikers carry heavy loads prefer to mount a U-shaped extension bar to the upper part of the packframe where bulky articles can be tied. A hiker normally tries to pack the heaviest articles as high as possible and as close to the back as possible. Bulky light weight articles, such as a sleeping bag, are normally carried below the packbag. The extended portion of the frame above the packbag is an ideal place for loading the heavier articles. Unfortunately, little thought has been given as to how they are to be retained. In the past this has been done by tying them or strapping them, usually to the U-shaped extension or to any other portion of the packframe that is available. Most hikers who have had to resort to this sytem have had the experience of arriving in camp only to discover that some critical item has fallen off along the way because it was not securely fastened. Romney and Joseph note the problem of carrying loads external to the packbag, but they do not provide any new solutions. Chanter's packframe is made of welded wire, and he notes that a perimeter slot "provides an enormous number of connecting points to the frame for straps", and that "miscellaneous items can easily be lashed to the frame at any point by means of straps, laces, or strings". Romney provides a packframe with a number of smaller bags or containers which can be tied on or removed independently at various positions on the frame. The packframe itself has a plurality of transversely extending knob-like members which provide anchors for lashing the pack units. The vertical frame members terminate in slotted plugs which also act as lashing points.
The Romney system is especially designed to use light weight cordage to secure edge grommetted pack units. However, where cordage is used for lashing other external loads which are often of awkward shape, it is inherently poor because of the small bearing area exerted against the object. Straps are generally superior. Unfortunately, solid anchor points for straps are often awkwardly placed or are not available at all in the location needed.
The present invention has overcome the above problems and is a significant step forward as a means of holding and retaining objects to a packframe external to the main packbag.